In printing apparatus generally and more particularly of interest to electrophotography or xerography, there is a need to provide control of temperature and humidity within the copier or printer machine in order to provide for optimum performance and ensure image quality. Heretofore, control of temperature and/or humidity was provided by employing individual sensors for each of humidity and temperature in the machine and controlling temperature of the certain component that was particularly critical, such as a photoconductor or xerographic imaging drum or belt, and controlling humidity at a different locations such as at the development station. Each is controlled to a particular set point. A problem with such an approach is that it is relatively energy inefficient and thus increases cost of production and operation of the machine. The other large printing machines employ expensive refrigeration units, which also adds to the cost and energy use of the machine.